U.S. patent application number 09/813628 was filed with the patent office on 2002-09-26 for merchandiser using slide-out stirling refrigeration deck.
Invention is credited to Rudick, Arthur G..
Application Number | 20020134089 09/813628 |
Document ID | / |
Family ID | 25212946 |
Filed Date | 2002-09-26 |
United States Patent
Application |
20020134089 |
Kind Code |
A1 |
Rudick, Arthur G. |
September 26, 2002 |
Merchandiser using slide-out stirling refrigeration deck
Abstract
A refrigerator. The refrigerator may include a cabinet and a
refrigeration deck slidably positioned within the cabinet. The
refrigeration deck may include a Stirling cooler unit.
Inventors: |
Rudick, Arthur G.; (Atlanta,
GA) |
Correspondence
Address: |
SUTHERLAND ASBILL & BRENNAN LLP
999 PEACHTREE STREET, N.E.
ATLANTA
GA
30309
US
|
Family ID: |
25212946 |
Appl. No.: |
09/813628 |
Filed: |
March 21, 2001 |
Current U.S.
Class: |
62/6 ;
62/448 |
Current CPC
Class: |
F25D 17/062 20130101;
F25B 2500/13 20130101; F25D 19/02 20130101; F25D 2317/0651
20130101; F25D 19/04 20130101; F25D 2317/0661 20130101; A47F 3/0443
20130101; F25B 2309/002 20130101; F25B 9/14 20130101 |
Class at
Publication: |
62/6 ;
62/448 |
International
Class: |
F25D 019/02; F25B
009/00 |
Claims
1. A refrigerator, comprising: a cabinet; and a refrigeration deck
slidably positioned within said cabinet; said refrigeration deck
comprising a Stirling cooler unit.
2. The refrigerator of claim 1, wherein said Stirling cooler unit
comprises a plurality of Stirling cooler units.
3. The refrigerator of claim 2, wherein said plurality of Stirling
cooler units comprises a plurality of free piston Stirling cooler
units.
4. The refrigerator of claim 3, wherein said plurality of Stirling
cooler units comprises a first one of said plurality of Stirling
cooler units out of phase with a second one of said plurality of
Stirling cooler units so as to cancel out the vibrations produced
by said plurality of Stirling cooler units.
5. The refrigerator of claim 1, wherein said Stirling cooler unit
comprises a fan.
6. The refrigerator of claim 1, wherein said Stirling cooler unit
comprises a hot end and a cold end.
7. The refrigerator of claim 6, wherein said refrigeration deck
comprises a hot air shroud positioned adjacent to said hot end of
said Stirling cooler unit.
8. The refrigerator of claim 6, wherein said refrigeration deck
comprises a cold end heat exchanger positioned adjacent to said
cold end of said Stirling cooler unit.
9. The refrigerator of claim 8, wherein said cold end heat
exchanger comprises a plate and a plurality of fins attached
thereto.
10. The refrigerator of claim 8, wherein said cold end of said
Stirling cooler unit attaches to said cold end heat exchanger via
an attachment ring.
11. The refrigerator of claim 1, wherein said cabinet comprises a
refrigerated space and an air plenum such that said air may
circulate through said air plenum between said refrigerated space
and said refrigeration deck.
12. The refrigerator of claim 11, wherein said air plenum comprises
a return air stream and a supply air stream.
13. The refrigerator of claim 12, wherein said refrigeration deck
comprises a cold air shroud positioned adjacent to said air
plenum.
14. The refrigerator of claim 13, wherein said refrigeration deck
comprises a fan positioned within said cold air shroud so as to
circulate air through said cabinet and said refrigeration deck.
15. The refrigerator of claim 1, wherein said refrigeration deck
comprise a base plate with a plurality of runners thereon so as to
slide said refrigeration deck in and out of said cabinet.
16. The refrigerator of claim 15, wherein each of said plurality of
runners comprises an isolation pad.
17. The refrigerator of claim 15, wherein said refrigeration deck
comprises a vertical wall extending from said base plate.
18. The refrigerator of claim 15, wherein said vertical wall
comprises an aperture therein, said aperture sized to accommodate
said Stirling cooler unit positioned therein.
19. The refrigerator of claim 18, wherein said refrigeration deck
comprises an insulation plug positioned within said aperture.
20. The refrigerator of claim 1, wherein said refrigeration deck
comprises an isolation mechanism, said isolation mechanism
supporting said Stirling cooler unit.
21. The refrigerator of claim 20, wherein said isolation mechanism
comprises an elastomeric layer positioned on a tray.
22. The refrigerator of claim 20, wherein said Stirling cooler unit
comprises a pin and a vertical plate with a screw positioned
thereon and wherein said tray comprises an up-turned tab with an
unthreaded hole and a down-turned tab with a threaded hole, such
that said pin may engage said unthreaded hole of said up-turned tab
and said screw may pass through said vertical plate and into said
threaded hole of said down-turned tab.
23. A refrigerator, comprising: a cabinet; and a refrigeration
deck; said refrigeration deck comprising a plurality of Stirling
cooler units; said plurality of Stirling cooler units comprising a
first one of said plurality of Stirling cooler units out of phase
with a second one of said plurality of Stirling cooler units so as
to cancel out the vibrations produced by said plurality of Stirling
cooler units.
24. The refrigerator of claim 23, wherein said refrigeration deck
comprises a plurality of isolation mechanisms, each said isolation
mechanism supporting one of said plurality of Stirling cooler
units.
25. The refrigerator of claim 24, wherein each of said plurality of
isolation mechanisms comprises an elastomeric layer positioned on a
tray.
26. The refrigerator of claim 23, wherein said refrigeration deck
comprise a base plate with a plurality of isolation pads
thereon.
27. The refrigerator of claim 26, wherein said refrigeration deck
comprises a vertical wall extending from said base plate.
28. The refrigerator of claim 27, wherein said vertical wall
comprises an aperture therein, said aperture sized to accommodate
said Stirling cooler unit positioned therein.
29. The refrigerator of claim 28, wherein said refrigeration deck
comprises an insulation plug positioned within said aperture.
30. A refrigeration deck for a refrigerator, comprising: a surface
extending in a first direction; a second surface extending in a
second direction, said second surface connected to said first
surface; said second surface comprising an aperture therein; said
second surface comprising an isolation tray positioned thereon; and
a Stirling cooler unit, said Stirling cooler unit positioned on
said isolation tray and extending through said aperture in said
second surface.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to refrigeration
systems that use a Stirling cooler as the mechanism for removing
heat from a desired space. More particularly, the present invention
relates to a glass door merchandiser with a slide-out Stirling
refrigeration deck.
BACKGROUND OF THE INVENTION
[0002] In the beverage industry and elsewhere, refrigeration
systems are found in vending machines, glass door merchandisers
("GDM's"), and other types of dispensers and coolers. In the past,
these units have used a conventional vapor compression (Rankine
cycle) refrigeration apparatus to keep the beverages or the
containers therein cold. In the Rankine cycle apparatus, the
refrigerant in the vapor phase is compressed in a compressor so as
to cause an increase in temperature. The hot, high-pressure
refrigerant is then circulated through a heat exchanger, called a
condenser, where it is cooled by heat transfer to the surrounding
environment. As a result of the heat transfer to the environment,
the refrigerant condenses from a gas back to a liquid. After
leaving the condenser, the refrigerant passes through a throttling
device where the pressure and temperature of the refrigerant are
reduced. The cold refrigerant leaves the throttling device and
enters a second heat exchanger, called an evaporator, located in or
near the refrigerated space. Heat transfer with the evaporator and
the refrigerated space causes the refrigerant to evaporate or to
change from a saturated mixture of liquid and vapor into a
superheated vapor. The vapor leaving the evaporator is then drawn
back into the compressor so as to repeat the cycle.
[0003] Stirling cycle coolers are also a well known as heat
transfer mechanisms. Briefly, a Stirling cycle cooler compresses
and expands a gas (typically helium) to produce cooling. This gas
shuttles back and forth through a regenerator bed to develop much
greater temperature differentials than may be produced through the
Rankine compression and expansion process. Specifically, a Stirling
cooler uses a displacer to force the gas back and forth through the
regenerator bed and a piston to compress and expand the gas. The
regenerator bed may be a porous element with a large thermal
inertia. During operation, the regenerator bed develops a
temperature gradient. One end of the device becomes hot and the
other end becomes cold. See David Bergeron, Heat Pump Technology
Recommendation for a Terrestrial Battery-Free Solar Refrigerator,
September 1998. Patents relating to Stirling coolers include U.S.
Pat. Nos. 5,678,409; 5,647,217; 5,638,684; 5,596,875 and 4,922,722
(all incorporated herein by reference).
[0004] Stirling cooler units are desirable because they are
nonpolluting, efficient, and have very few moving parts. The use of
Stirling coolers units has been proposed for conventional
refrigerators. See U.S. Pat. No. 5,438,848 (incorporated herein by
reference). However, it has been recognized that the integration of
a free-piston Stirling cooler into a conventional refrigerated
cabinet requires different manufacturing, installation, and
operational techniques than those used for conventional compressor
systems. D. M. Berchowitz et al., Test Results for Stirling Cycle
Cooler Domestic Refrigerators, Second International Conference. As
a result, the use of the Stirling coolers in, for example, beverage
vending machines, GDM's, and other types of dispensers, coolers, or
refrigerators is not well known.
[0005] For example, Stirling coolers by their nature produce a
small amplitude vibration. Care must be taken to isolate
vibrationally the Stirling cooler unit from the cabinet. If
vibrations are transmitted from the Stirling cooler unit to the
cabinet, the results may range from an annoying noise to even a
potential reduction in the life of the refrigeration device as a
whole.
[0006] A need exists, therefore, for adapting Stirling cooler unit
technology to conventional beverage vending machines, GDM's,
dispensers, coolers, refrigerators, and the like. Specifically, the
Stirling cooler units used therein should be easily accessible in
case of repair or replacement. Preferably, the Stirling coolers
should be accessible with a minimum of down time for the enclosure
as a whole and without the need for emptying the enclosure. The
beverage vending machine, GDM, or other type of dispenser, cooler,
or refrigerator with the Stirling cooler units therein should be
both easy to use and energy efficient. The Stirling cooler units
also should be positioned therein so as to produce a minimum of
vibration to the enclosure as a whole.
SUMMARY OF THE INVENTION
[0007] The present invention thus provides for a refrigerator. The
refrigerator may include a cabinet and a refrigeration deck
slidably positioned within the cabinet. The refrigeration deck may
include a Stirling cooler unit.
[0008] Specific embodiments of the invention may include the use of
a number of Stirling cooler units. The Stirling cooler units may be
free piston Stirling cooler units. One of the Stirling cooler units
may be operated out of phase with a second one of the units so as
to cancel out the vibrations produced by all of the Stirling cooler
units. The Stirling cooler units may each include a fan, a hot end,
and a cold end. A hot air shroud may be positioned adjacent to the
hot end and a cold end heat exchanger may be positioned adjacent to
the cold end. The cold end heat exchanger may include a plate and a
number of fins attached thereto. The cold end of the Stirling
cooler unit may be attached to the cold end heat exchanger via an
attachment ring.
[0009] The cabinet may include a refrigerated space and an air
plenum such that the air may circulate through the air plenum
between the refrigerated space and the refrigeration deck. The air
plenum may include a return air stream and a supply air stream. The
refrigeration deck may include a cold air shroud positioned
adjacent to the air plenum. The refrigeration deck also may include
a fan positioned within the cold air shroud so as to circulate the
air through the cabinet and the refrigeration deck.
[0010] The refrigeration deck may include a base plate with a
number of runners thereon so as to slide the refrigeration deck in
and out of the cabinet. The runners each may include an isolation
pad. The refrigeration deck also may include a vertical wall
extending from the base plate. The vertical wall may include an
aperture therein. The aperture may be sized to accommodate a
Stirling cooler unit therein. An insulation plug also may be
positioned within the aperture.
[0011] The refrigeration deck may include an isolation mechanism.
The isolation mechanism may support the Stirling cooler unit. The
isolation mechanism may include an elastomeric layer positioned on
a tray. The Stirling cooler unit may include a pin and a vertical
plate with a screw positioned thereon. The tray may include an
up-turned tab with an unthreaded hole and a down-turned tab with a
threaded hole. The pin may engage the unthreaded hole of the
upturned tab and the screw may pass through the vertical plate and
into the threaded hole of the down-turned tab.
[0012] A further embodiment of the present invention may provide
for a refrigerator. The refrigerator may include a cabinet and a
refrigeration deck. The refrigeration deck may include a number of
Stirling cooler units. One of the Stirling cooler units may be out
of phase with a second one of the units so as to cancel out the
vibrations produced by the Stirling cooler units as a whole.
[0013] The refrigeration deck may include a number of isolation
mechanisms. Each of the isolation mechanisms may support one of the
Stirling cooler units. Each of the isolation mechanisms may have an
elastomeric layer positioned on a tray. The refrigeration deck may
have a base plate with a number of isolation pads thereon. The
refrigeration deck also may include a vertical wall extending from
the base plate. The vertical wall may include an aperture therein.
The aperture may be sized to accommodate the Stirling cooler unit
therein. The aperture also may include an insulation plug.
[0014] A further embodiment of the present invention may provide
for a refrigeration deck for a refrigerator. The refrigeration deck
may include a surface extending in a first direction and a second
surface extending in a second direction. The second surface may be
connected to the first surface. The second surface may include an
aperture therein and an isolation tray positioned thereon. A
Stirling cooler unit may be positioned on the isolation tray and
extend through the aperture in the second surface.
[0015] These and other objects, features, and advantages of the
present invention will become apparent after review of the
following detailed description of the disclosed embodiments and the
appended drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a Stirling cooler unit.
[0017] FIG. 2 is a partial cross-sectional view of the Stirling
cooler unit taken along line 2-2 of FIG. 1.
[0018] FIG. 3 is a front view of a glass door merchandiser with a
slide-out refrigeration deck having four (4) Stirling cooler units
therein.
[0019] FIG. 4 is a cross-sectional view through the cabinet of the
glass door merchandiser taken along line 4-4 of FIG. 3.
[0020] FIG. 5 is a cross-sectional view through the cabinet of the
glass door merchandiser and the refrigeration deck taken along line
5-5 of FIG. 3.
[0021] FIG. 6 is an enlarged view of FIG. 5 showing the Stirling
cooler unit mounted within the refrigeration deck.
[0022] FIG. 7 is a pictorial view of the Stirling cooler units
operated out of phase with each other.
[0023] FIG. 8 is a cross-sectional view taken through the cabinet
and the refrigeration deck along line 8-8 of FIG. 3.
[0024] FIG. 9 is an exploded view of the fan and the cold air
shroud assembly.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] With reference to the drawings in which like numerals
indicate like elements throughout the several views, the present
invention utilizes one or more Stirling cooler units 100. The
Stirling cooler units 100 in general are well known to those
skilled in the art. One type of Stirling cooler unit 100 that may
be used in the present invention is a free piston Stirling cooler.
For example, the Stirling cooler unit 100 for use herein may be
commercially available from Global Cooling, Inc. of Athens, Ohio
under the designation "M100B". Other types of Stirling cooler units
100 that may be useful with the present invention are shown in U.S.
Pat. Nos. 5,678,409; 5,647,217; 5,638,684; 5,596,875; 5,438,848;
and 4,922,722, the disclosures of which are incorporated herein by
reference.
[0026] As is shown in FIGS. 1 and 2, the Stirling unit 100 may
include an acceptor or a cold end 110 and a rejector or a hot end
120. The hot end 120 may be surrounded by a hot end heat exchanger
130. A regenerator 140 may separate the cold end 110 and the hot
end 120. The regenerator 140 may include a bed of closely spaced
layers of Mylar (polyester film) or similar types of materials. The
internal refrigerant may be helium, hydrogen, or similar types of
fluids. The Stirling unit 110 may further include a piston 145
driven by a linear motor (not shown). The piston 145 and the linear
motor may be positioned within a shell 150. The shell 150, in turn,
may be positioned upon a spring mounted balance mass 160. A heat
rejection shroud 170 may surround the linear motor and the shell
150. The heat rejection shroud 170 may be made out of plastic,
sheet metal, or similar materials. A fan 180, or another type of
air movement device, may be positioned within the shroud 170. The
fan 180 may direct a flow of ambient air through the hot end heat
exchanger 130 as is shown by the arrows 190 in FIG. 2. The fan 180
may have a free air capacity of about thirty (30) to about one
hundred ten (110) cubic inches per second. The functions of these
internal elements of the Stirling units 100 are well known to those
skilled in the art, and therefore, will not be explained further.
Likewise, the respective sizes of the Stirling cooler units 100 and
the components therein will vary with the specific application and
the operating environment.
[0027] FIGS. 3 and 4 show a glass door merchandiser 200 ("GDM 200")
for use with the present invention. Although the GDM 200 is shown,
the invention also could work with conventional beverage vending
machines, other types of beverage dispensers, or any other type of
refrigerator or refrigerated space. The GDM 200 may include a
cabinet 205 with an upper part 210 and a lower part 215. The
cabinet 205 also may include a refrigerated section 220, a
refrigeration deck area 225, and a false back 230. Positioned
beneath the refrigeration deck area 225 may be a drain pan 226. The
drain pan 226 may collect condensate from the operation of the
Stirling units 100 as is explained in more detail below. A drain
tube 227 extending from the refrigeration deck area 225 may feed
condensate to the drain pan 226.
[0028] The false back 230 separates the refrigerated section 220 of
the cabinet 205 from an air plenum 235. The air plenum 235 may be
used to circulate air between the refrigerated section 220 and the
refrigeration components within the refrigeration deck area 225 as
is described below. The air plenum 235 may include an inside
channel 240 and two outside channels 245. Two dividers 250 may
separate the channels 240, 245. The false back 230 also may include
several louvers 255 positioned adjacent to the outside channels
245. The louvers 255 may allow return air from the refrigerated
section 220 to enter the downward flowing air stream back towards
the refrigeration components within the refrigeration deck area
225. The false back 230 also may include a number of inside louvers
256 positioned adjacent to the inside channel 240. The inside
louvers 256 may allow some of the supply air to leave the upward
flowing channel of the air plenum 235 and enter the refrigerated
section 220. Although the term "louver" is used herein, any type of
air passageway may be employed. Likewise, the respective upwards
and downwards air flows may be reversed. The false back 230 may
stop short of the top of the upper part 210 of the cabinet 205 so
as to allow the remaining upward airflow to enter the refrigerated
section 220 of the cabinet 205 and circulate therein.
[0029] A refrigeration deck 260 may be positioned within the
refrigeration deck area 225 of the lower part 215 of the cabinet
205. As is shown in FIG. 3, four (4) Stirling units 100 may be used
within the refrigeration deck 260, a first unit 101, a second unit
102, a third unit 103, and a fourth unit 104. The GDM 200, however,
can use any number of Stirling units 100. As described above, the
number of Stirling units 100 used may depend on the refrigeration
capacity needed for the GDM 200 as a whole and the refrigeration
capacity of each Stirling unit 100. The refrigeration deck 260 also
may be located in the upper part 210 of the cabinet 205 in the same
or a similar manner of installation.
[0030] Referring to FIGS. 5 through 8, the refrigeration deck 260
may include a base plate 300. The base plate 300 may be made out of
steel, aluminum, or similar types of materials. The base plate 300
may include a number of runners 310 positioned thereon. The runners
310 may be made out of steel, aluminum, or similar types of
materials. The runners 310 may allow the base plate 300, and the
refrigeration deck 260 as a whole, to slide in and out of the lower
part 215 of the cabinet 205. The base plate 300 may be connected
the runners 310 via a number of pads 320. The pads 320 may be made
from an elastomeric material such as polyurethane, neoprene
(polychloroprene), or similar types of materials. The pads 320 may
provide or improve vibration isolation for the refrigeration deck
260 as a whole.
[0031] The refrigeration deck 260 may include a vertical wall 330
connected to the base plate 300. The vertical wall 330 may be made
out of a foam laminated with a steel skin or similar types of
materials or structures. The vertical wall 330 may be insulated
with expanded polystyrene foam, polyurethane foam, or similar types
of materials. The vertical wall 330 may be attached to the base
plate 300 and stabilized by one or more side brackets 340. One of
the side brackets 340 may be positioned on either side of the
vertical wall 330. Also attached to the vertical wall 330 may be a
hot air shroud 345. The hot air shroud 345 may be made out of
steel, plastic, or similar types of materials. The hot air shroud
345 may include a number of shroud apertures 350 sized to
accommodate the Stirling units 100. The hot air shroud 345 also may
include a bottom opening 355 that extends through the base plate
300. The bottom opening 355 may assist in circulating the waste
heat of the Stirling units 100 as explained in more detail
below.
[0032] The Stirling units 100 may be attached to the refrigeration
deck 260 via the base plate 300 and the vertical wall 330.
Specifically, the Stirling units 100 each may rest on a primary
vibration isolation mechanism 360. The details of these isolation
mechanisms 360 will be described in detail below. The top Stirling
units 100 may be supported via the isolation mechanisms 360 by a
horizontal bracket 370. The horizontal bracket 370 may be attached
at both ends to the side brackets 340. The bottom Stirling units
100 may be supported via the isolation mechanisms 360 attached to
the base plate 300.
[0033] Each isolation mechanism 360 may include a soft block 400
bonded to a tray 410. The soft block 400 may be made out of a
compliant elastomeric material such as polyurethane, neoprene
(polychloroprene), or similar types of materials. In the case of
the upper Stirling units 100, the soft block 400 may be bonded to
and supported by the horizontal bracket 370. In the case of the
lower Stirling units 100, the soft block 400 may be bonded to and
supported by the base plate 300. As is shown in more detail in FIG.
6, the tray 410 may have an up-turned tab 420 with an unthreaded
hole 430 on one end and a down-turned tab 440 with a threaded hole
450 on the other end. A pin 460 may be mounted on one end of the
hot air shroud 170 of each Stirling unit 100 while a vertical plate
470 with a screw 480 may be mounted on another end. When the
Stirling unit 100 is installed, the pin 460 may engage the
unthreaded hole 430 of the up-turned tab 420 and the screw 480 may
pass through the vertical plate 470 and into the threaded hole 450
of the down-turned tab 440 so as to secure the unit 100.
[0034] The Stirling units 100 also may be attached into and through
the vertical wall 330 via a number of cooler apertures 500
positioned therein. Each Stirling unit 100 may be positioned within
a cooling aperture 500 such that each cold end 110 extends through
the vertical wall 330. Each of the cold ends 110 then may be
attached to a cold end heat exchanger 510. The cold end heat
exchanger 510 may be of conventional design and may include a plate
520 with a number fins 530 attached thereto. The cold end heat
exchanger 510 may be made out of cast aluminum or similar materials
with good heat transfer characteristics.
[0035] Each Stirling unit 100 may be attached to the cold end heat
exchanger 510 via a number of screws 540 and a number of attachment
rings 550. Each attachment ring 550 may have flange 560 that
surrounds and engages the back end of the cold end 110 of each
Stirling unit 100. The attachment ring 550 thus secures the
Stirling unit 100 to the cold end heat exchanger 510. Any
additional space remaining within the vertical wall apertures 500
may be filled with an insulation plug 570. The insulation plugs 570
may be substantially toroidal in shape and may be made out of a
soft compliant foam or other materials with good insulating,
vibration, and isolation characteristics.
[0036] When the Stirling units 100 are firmly attached to the cold
end heat exchanger 510, the units 100 and the heat exchanger 510
may be substantially isolated with respect to vibrations from the
remainder of the GDM 200. The only points of contact between the
Stirling units 100 and the GDM 200 may include the trays 410, the
attachment rings 550, and the insulation plugs 570. Due to the
nature of the material therein, the isolation plugs 570 should not
transmit significant vibration from the Stirling units 100 to the
vertical wall 330. The insulation plugs 570 thus provide the
Stirling cooler units 100 with vibration isolation in that the
Stirling cooler units 100 and the cold end heat exchanger 520
essentially "float" with the isolation plugs 570.
[0037] Significantly, the respective Stirling units 100 may be
positioned within the refrigeration deck 260 such that the units
100 largely cancel out the vibrations of each other. For example,
the units 100 on the opposite diagonals may be operated in opposite
phases. Specifically, the unit 101 and the unit 104 may operate in
one phase while the unit 102 and the unit 103 may operate in the
opposite phase, i.e., the units 100 on the opposite diagonals are
180 degrees out of phase with each other. By out of phase, we mean
the respective internal piston strokes are reversed as is shown in
FIG. 7. Because the vibrations of the units 101, 104 are 180
degrees out of phase with units 102, 103, the vibrations tend to
cancel each other out and hence reduce the amount of vibrations
transmitted to the GDM 200 as a whole. Changing the phase on the
units 100 generally involves flipping the position of an internal
connector (not shown) as attached to the incoming power line (not
shown).
[0038] As is shown in FIGS. 8 and 9, a cold air shroud 580 also may
be attached to the vertical wall 330. The cold air shroud 580 may
include a heat exchanger enclosure 582 and a fan enclosure 585. The
enclosures 580, 582 may be joined by conventional means such as pop
riveting or other methods. The cold air shroud 580 may be made out
of aluminum, steel, or similar types of materials. A fan 590, or
another type of air movement device, may be mounted within the cold
air shroud 580 by a support bracket 600. Although the term "fan"
590 is used herein, the fan may be any type of air movement device,
such as a pump, a bellows, a screw, and the like known to those
skilled in the art. The fan 590 may be driven by a conventional
electric motor 610. The fan 590 may have a capacity of about 300 to
500 cubic feet per minute.
[0039] To insert the Stirling units 100 and the refrigeration deck
260 into the GDM 200, the refrigeration deck 260 may be slid into
position within the cabinet 205 by the runners 310 of the base
plate 300. The cabinet 205 may contain a primary seal 650 that
extends on the perimeter of the lower portion 220 along a seal
flange 655. Likewise, the vertical wall 330 of the refrigeration
deck 260 may align with the primary seal 650 of the cabinet 205.
Further, the cabinet 205 also may have a secondary seal 670
positioned along a secondary seal flange 675 that aligns with the
cold air shroud 580 of the refrigeration deck 260. The seals 650,
670 may be made out of neoprene foam (polychloroprene), vinyl
extrusion, or similar materials with good insulating
characteristics. When the refrigeration deck 260 is completely
positioned within the cabinet 205, the primary seal 650 is
compressed between the vertical wall 330 and the seal flange 655
while the secondary seal 670 is compressed between the cold air
shroud 580 and the secondary seal flange 675. The seals 650, 670
thus form relatively airtight boundaries for thermal efficiency for
the GDM 200 as a whole.
[0040] In use, air flowing in the outside channels 245 of the air
plenum 235 enters into the cold end heat exchanger 510. The air is
drawn through the cold end heat exchanger 510 by the fan 590. Heat
in the air stream is absorbed by the cold end heat exchanger 510 as
the air stream passes through. The air is then directed into the
upward flowing inside air channel 240 through the cold air shroud
580. The dashed arrows 700 in FIG. 8 show the general direction of
the air stream. The air is then circulated though the refrigerated
section 220 of the cabinet 205 and back to the refrigeration deck
260. Any condensate formed about the cold end heat exchanger 510
may pass through the drain tube 227 to the drain pan 226.
[0041] On the opposite side of the vertical wall 330, the hot air
shroud 345 directs the waste heat from the Stirling units 100
through the bottom opening 355 in the base plate 300 as is shown by
the dashed arrows 710 in FIG. 5. The internal fans 180 of the
Stirling units 100 may produce the airflow. The waste heat may
circulate over the top of the drain pan 226 so as to evaporate the
condensate therein.
[0042] In order to remove the Stirling unit 100 and the
refrigeration deck 260 as a whole, the refrigeration deck 260 may
be slid along the runners 310 of the base plate 300 and removed
from the cabinet 205. The refrigerated section 220 need not be
emptied of product when removing the refrigeration deck 260. The
cold air shroud 580 may then be removed from the vertical wall 330.
The individual Stirling unit 100 may then be removed by removing
the screws 480, 540. The Stirling unit 100, along with the pin 460,
the vertical plate 470, the attachment ring 550, and the insulation
plugs 570 may then be removed. A new Stirling unit 100, along with
the same components, may then be slid into place. The refrigeration
deck 260 may then be replaced in the same manner as described
above.
[0043] The present invention thus results in a GDM 200 with an
easily removable refrigeration deck 260 for access to the Stirling
units 100. The invention thus provides the efficiencies of the
Stirling units 100 with improved access and versatility. Further,
the invention limits the amount of vibration transferred from the
Stirling units 100 to the GDM 200 as a whole. First, the Stirling
units 100 may be operated out of phase so as to cancel out the
vibrations produced by each unit 100. Second, the pads 320, the
isolation mechanism 360, and the isolation plugs 570 serve to
"float" the Stirling units 100 so as to limit the amount of
vibration even further.
[0044] It should be apparent that the foregoing relates only to the
preferred embodiments of the present invention and that numerous
changes and modifications may be made herein without departing from
the spirit and scope of the invention as defined by the following
claims.
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